We do...but not for instrument practice. Now, if you were just learning how to read music, that'd be one thing. But actually practicing an instrument (a flute, in this case) in a study room? Nope, sorry. The rooms, although they look it, aren't sound-proof. And a lot of patrons would be very upset if the sounds of a flute started wafting around the library air.
(Now, I wouldn't mind personally, being a flautist myself, but that's just me. I can't speak for any of the patrons who are studying etc in the library.)